docs: def exportItem(self,
                     title,
                     itemId,
                     exportFormat,
                     tags="export",
                     snippet=None,
                     exportParameters=None,
                     wait=True):
          """
          Exports a service item (POST only) to the specified output format.
          Available only to users with an organizational subscription.
          Invokable only by the service item owner or an administrator.
  
          Inputs:
             title - name of export item
             itemId - id of the item to export
             exportFormat - out format. Values: Shapefile, CSV or File
                            Geodatabase, feature collection, GeoJson,
                            or Scene Package
             tags - comma seperated list of quick descriptors, the default is
              export.
             snippet - short explination of the exported item
             exportParameters - A JSON object describing the layers to be
                                exported and the export parameters for each
                                layer.
             wait - optional - default false. Export item is an a synchronus
              operation. If true is specified, the process will wait till the
              operation is completed.
          Output:
             If wait is True:
                UserItem class
             else:
                job id for the export item.
          """
          url = "%s/export" % self.location
          params = {
              "f" : "json",
              "title" : title,
              "tags" : tags,
              "itemId" : itemId,
              "exportFormat" : exportFormat,
          }
          if snippet is not None:
              params['snippet'] = snippet
          if exportParameters is not None:
              params["exportParameters"] = json.dumps(exportParameters)
          res = self._post(url=url,
                              param_dict=params,
                              securityHandler=self._securityHandler,
                              proxy_port=self._proxy_port,
                              proxy_url=self._proxy_url)
          itemURL = "%s/items/%s" % (self.location, res['exportItemId'])
          if self.currentFolder is not None or self.currentFolder['title'] != "root":
              self.moveItems(items=res['exportItemId'], folder=self.currentFolder['id'])
          ui = UserItem(url=itemURL,
                        securityHandler=self._securityHandler,
                        proxy_url=self._proxy_url,
                        proxy_port=self._proxy_port)
          if wait == True:
              status = "partial"
              while status != "completed":
                  status = ui.status(jobId=res['jobId'], jobType="export")
                  if status['status'] == 'failed':
                      raise Exception("Could not export item: %s" % itemId)
                  elif status['status'].lower() == "completed":
                      break
                  time.sleep(2)
          else:
              return res['jobId'], ui
          return ui